[TRNSYS-users] Air couplings TRNBuild

[David BRADLEY]

Maja,

  The air coupling option simply allows air to pass directly from one 
zone to another. As with many things in Type56 you can choose to specify 
a constant amount, a scheduled amount, or an input amount that will come 
from some other model or from an equation. The question, of course, is 
how to know how much air will flow from one node to another. In very 
simple HVAC systems you might know; if you have a VENTILATION supply in 
one zone and you know that the only return is in a neighboring zone then 
it is a fairly simple matter of setting the quantity of air that passes 
between the two nodes. In more complex systems you need to couple the 
Type56 thermal model of the building with an airflow model that will 
estimate the internodal air transfers. There are two options. One is 
TRNFLow, which is a commercially available add-on to Trnsys. It uses the 
same TRNBuild interface but allows you to define airflow links between 
airnodes. It uses an engine called COMIS to determine air flow rates. 
The other alternative is to use CONTAM/Type97. Type97 is a standard 
component and the CONTAM interface is freely available 
(https://www.nist.gov/services-resources/software/contam). The 
disadvantage is that you'll need to reenter a good bit of building 
information into the CONTAM interface. There is an example of a building 
coupled with a CONTAM airflow model in the .\Trnsys18\Examples\ 
directory if you want to have a look.

kind regards,

  David


On 04/05/2022 06:42, Maja Danovska via TRNSYS-users wrote:
> Dear Users,
>
> I would like someone to explain to me better the AIR COUPLING option 
> in every single thermal zone, when it should be used, and how...
>
> I have a geometrical model of a library which was divided into 
> different thermal zones, some of them with real boundaries (i.e., 
> walls), others with virtual surfaces or maybe modelled with a ceiling 
> but in reality there you have stairs, so the volumes are connected. 
> This is just an example. Where should I use the air coupling?
>
> Thanks in advance.
>
> Kind regards
>
> -- 
> *Maja Danovska*
> *
> *
> Research Fellow
> Dep. of Civil, Environmental and Mechanical Engineering
> University of Trento
> via Mesiano, 77 - 38123 - Trento - ITALY
>
> maja.danovska at unitn.it
> +393403391289
>
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> TRNSYS-users at lists.onebuilding.org
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-- 
***************************
David BRADLEY
Principal
Thermal Energy System Specialists, LLC
3 North Pinckney Street - suite 202
Madison, WI  53703 USA

P:+1.608.274.2577
d.bradley at tess-inc.com

http://www.tess-inc.com
http://www.trnsys.com
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